The present teachings relate generally to materials useful in orthopaedic surgery, including orthopaedic implants composed of resorbable materials.
In general, the human musculoskeletal system is composed of a variety of tissues including bone, ligaments, cartilage, muscle, and tendons. Tissue damage or deformity stemming from trauma, pathological degeneration, or congenital conditions often necessitates surgical intervention to restore function. During these procedures, surgeons can use orthopaedic implants to restore function to the site and facilitate the natural healing process.
Current orthopaedic implants are generally composed of non-resorbable metals, ceramics, polymers, and composites. However, in some instances, it may be desirable to have an implant made of resorbable material. These bioresorbable or biodegradable materials are characterized by the ability to be chemically broken down into harmless by-products that are metabolized or excreted by the body. Materials of this type can offer an advantage over conventional non-resorbable implant materials. Bioresorbable implants provide their required function until the tissue is healed, and once their role is complete, the implant is resorbed by the body. The end result is healthy tissue with no signs that an implant was ever present.
Bioresorbable materials are substances well known in the art. This includes resorbable polymers such as poly(lactic acid) [PLA] and poly(glycolic acid) [PGA], and ceramics such as hydroxyapatite, tricalcium phosphate, and calcium carbonate. Additionally, polymer/ceramic composites have also been used as an implant material. Overall, these materials have been used to fabricate a large range of orthopaedic implants including screws, plates, pins, rods, spacers, and the like. Clinically, these devices have a long history of use that spans a wide variety of surgical procedures. Resorbable devices have been used in applications such as fracture fixation, bone grafting, spinal fusion, soft tissue repair, and deformity correction.